Display systems, such as digital micro-mirror device (DMD) and liquid crystal display (LCD) projectors, project high-quality images onto a viewing surface. Both DMD and LCD projectors utilize high-intensity lamps and reflectors to generate the light needed for projection. Light generated by the lamp is concentrated as a “fireball” that is located at a focal point of a reflector. Light produced by the fireball is directed into a projection assembly that produces images and utilizes the generated light to form the image. The image is then projected onto a viewing surface.
Efforts have been directed at making projectors more compact while making the image of better quality. As a result, lamps utilized have become more compact and of higher intensity. In addition to generating light, these lamps also produce heat. In general, the higher the intensity of light generated, the greater the heat generated. A portion of this heat is frequently removed by directing cool air over the reflector.
Several factors may affect the cooling of the display system. Some systems simply cut power to the lamp assembly if these factors cause the temperature of the lamp to rise above a certain temperature. However, simply cutting power to the lamp when adverse conditions exist may be undesirable, for example, if the projector is used in a presentation, the projector will shutdown until the system cools down. After a cool down interval, the projector may be restarted to continue the presentation until the overheat conditions repeat.